LU-4257 llite: fast read implementation

[fs/lustre-release.git] / lustre / llite / rw.c

diff --git a/lustre/llite/rw.c b/lustre/llite/rw.c
index 1626d89..0f07927 100644 (file)
--- a/lustre/llite/rw.c
+++ b/lustre/llite/rw.c
@@ -1048,7 +1048,8 @@ struct ll_cl_context *ll_cl_find(struct file *file)
        return found;
 }
 
-void ll_cl_add(struct file *file, const struct lu_env *env, struct cl_io *io)
+void ll_cl_add(struct file *file, const struct lu_env *env, struct cl_io *io,
+              enum lcc_type type)
 {
        struct ll_file_data *fd = LUSTRE_FPRIVATE(file);
        struct ll_cl_context *lcc = &ll_env_info(env)->lti_io_ctx;
@@ -1058,6 +1059,7 @@ void ll_cl_add(struct file *file, const struct lu_env *env, struct cl_io *io)
        lcc->lcc_cookie = current;
        lcc->lcc_env = env;
        lcc->lcc_io = io;
+       lcc->lcc_type = type;
 
        write_lock(&fd->fd_lock);
        list_add(&lcc->lcc_list, &fd->fd_lccs);
@@ -1075,11 +1077,11 @@ void ll_cl_remove(struct file *file, const struct lu_env *env)
 }
 
 static int ll_io_read_page(const struct lu_env *env, struct cl_io *io,
-                          struct cl_page *page)
+                          struct cl_page *page, struct file *file)
 {
        struct inode              *inode  = vvp_object_inode(page->cp_obj);
        struct ll_sb_info         *sbi    = ll_i2sbi(inode);
-       struct ll_file_data       *fd     = vvp_env_io(env)->vui_fd;
+       struct ll_file_data       *fd     = LUSTRE_FPRIVATE(file);
        struct ll_readahead_state *ras    = &fd->fd_ras;
        struct cl_2queue          *queue  = &io->ci_queue;
        struct vvp_page           *vpg;
@@ -1091,7 +1093,8 @@ static int ll_io_read_page(const struct lu_env *env, struct cl_io *io,
        uptodate = vpg->vpg_defer_uptodate;
 
        if (sbi->ll_ra_info.ra_max_pages_per_file > 0 &&
-           sbi->ll_ra_info.ra_max_pages > 0) {
+           sbi->ll_ra_info.ra_max_pages > 0 &&
+           !vpg->vpg_ra_updated) {
                struct vvp_io *vio = vvp_env_io(env);
                enum ras_update_flags flags = 0;
 
@@ -1152,14 +1155,61 @@ int ll_readpage(struct file *file, struct page *vmpage)
 
        env = lcc->lcc_env;
        io  = lcc->lcc_io;
-       LASSERT(io != NULL);
+       if (io == NULL) { /* fast read */
+               struct inode *inode = file_inode(file);
+               struct ll_file_data *fd = LUSTRE_FPRIVATE(file);
+               struct ll_readahead_state *ras = &fd->fd_ras;
+               struct vvp_page *vpg;
+
+               result = -ENODATA;
+
+               /* TODO: need to verify the layout version to make sure
+                * the page is not invalid due to layout change. */
+               page = cl_vmpage_page(vmpage, clob);
+               if (page == NULL) {
+                       unlock_page(vmpage);
+                       RETURN(result);
+               }
+
+               vpg = cl2vvp_page(cl_object_page_slice(page->cp_obj, page));
+               if (vpg->vpg_defer_uptodate) {
+                       enum ras_update_flags flags = LL_RAS_HIT;
+
+                       if (lcc->lcc_type == LCC_MMAP)
+                               flags |= LL_RAS_MMAP;
+
+                       /* For fast read, it updates read ahead state only
+                        * if the page is hit in cache because non cache page
+                        * case will be handled by slow read later. */
+                       ras_update(ll_i2sbi(inode), inode, ras, vvp_index(vpg),
+                                  flags);
+                       /* avoid duplicate ras_update() call */
+                       vpg->vpg_ra_updated = 1;
+
+                       /* Check if we can issue a readahead RPC, if that is
+                        * the case, we can't do fast IO because we will need
+                        * a cl_io to issue the RPC. */
+                       if (ras->ras_window_start + ras->ras_window_len <
+                           ras->ras_next_readahead + PTLRPC_MAX_BRW_PAGES) {
+                               /* export the page and skip io stack */
+                               vpg->vpg_ra_used = 1;
+                               cl_page_export(env, page, 1);
+                               result = 0;
+                       }
+               }
+
+               unlock_page(vmpage);
+               cl_page_put(env, page);
+               RETURN(result);
+       }
+
        LASSERT(io->ci_state == CIS_IO_GOING);
        page = cl_page_find(env, clob, vmpage->index, vmpage, CPT_CACHEABLE);
        if (!IS_ERR(page)) {
                LASSERT(page->cp_type == CPT_CACHEABLE);
                if (likely(!PageUptodate(vmpage))) {
                        cl_page_assume(env, io, page);
-                       result = ll_io_read_page(env, io, page);
+                       result = ll_io_read_page(env, io, page, file);
                } else {
                        /* Page from a non-object file. */
                        unlock_page(vmpage);